WASHINGTON (AP) _ More American Indians drifted away from reservations and tribal lands in the last decade, the Census Bureau said Wednesday. Many were looking for jobs.

''Indian reservations are similar to undeveloped nations around the world,'' said Duane Beyal, a spokesman for the Navaho Nation in Window Rock, Ariz. ''The only difference is we're in America.''

The 1990 census found 35 percent of the nation's 2 million American Indians, Eskimos and Aleuts lived in areas governed by tribes. That's down from 37 percent in 1980.

The Navaho Nation reservation is the most populous in the nation with 143,405 American Indians living there, the Census Bureau said.

The census found 685,464 American Indians, Eskimos and Aleuts lived on tribal lands. Nearly 1.3 million lived outside American Indian areas.

While the numbers don't specifically track migration from reservations, Beyal said many young people leave to find work.

''It has been an ongoing thing for quite a few years now,'' Beyal said. ''That's simply because there are limited opportunities for young people on our reservations. That's just a fact of life.''

The reservations with the largest American Indian populations, after the Navaho Nation, are Pine Ridge in Nebraska and South Dakota, 11,182; Fort Apache, Ariz., 9,825; Gila River, Ariz., 9,116; Papago, Ariz., 8,480; Rosebud, S.D., 8,043; San Carlos, Ariz., 7,110; Zuni Pueblo in Arizona and New Mexico, 7,073; Hopi, Ariz., 7,061; and Blackfoot, Mont., 7,025.

The urban areas with the greatest American Indian populations are Los Angeles, 87,487; Tulsa, Okla., 48,196; New York, 46,191; Oklahoma City, 45,720; San Francisco, 40,847; Phoenix, 38,017; Seattle-Tacoma, 32,071; Minneapolis-St. Paul, 23,956; Tucson, 20,330; and San Diego, 20,066.

Since the 1950s, more than 200,000 American Indians have moved from tribal lands with government help.

But Beyal said those who leave tribal lands don't go far. ''Many of them are still in touch with home,'' he said. ''They're able to visit on weekends. Many return for such things as ceremonies in the summertime.''